Amerisur Resources to Begin Drilling Platanillo-1 in September

Amerisur Resources reports that the civil works are complete for Platanillo-1 and the operator, Ecopetrol, has authorized the mobilization of the Pride-17 drilling rig to the well location. The rig mobilization is scheduled to take approximately three weeks and Amerisur expects the well to spud during the first half of September 2007, followed by testing and results in October 2007.

The Platanillo-2 well will be drilled "back-to-back" with Platanillo-1, using the same rig. The location of the well will depend on the results obtained in Platanillo-1. Subject to the possibility of additional civil works, it is expected Platanillo-2 will be spudded during October 2007.

Amerisur expects the workover rig Pride-6 will be mobilized to the Alea-1 location during the first half of September 2007. Alea is an existing discovery, made in 1988, when the well flowed at rates of up to 533 barrels per day. It is anticipated that re-entry operations will commence during the second half of September, followed by testing and results in October 2007.

Negotiations continue with respect to the acquisition of an increased working interest in the Platanillo contract. Any such change in participation would be subject to approval by ANH

Current working interests in this block are Ecopetrol as operator with 40%; Repsol YPF with 355; Amerisur Resources with 25%.